Stabilized polyvinyl chloride resins



United States Patent STABILIZED POLYVINYL CHLORIDE RESINS William E. Leistner, Brooklyn, and Arthur 'C. Hecker, Richmond Hill, N.Y., assignors to Argus Chemical Laboratory, Inc., a corporation of New York No Drawing. Application November 10, 1953 Serial No. 391,378

2 Claims. (Cl. 260-4515) The present invention relates to chlorine-containing organic compositions stabilized by organic derivatives of tetravalent tin. This is a continuation-in-part of our copending application, Serial No. 315,182, filed October 16, 1952.

The stabilizing tin compounds are derived from tetravalent tin by having at least one valence and at the utmost three valences linked to the sulfur atom of an ester of a mercapto alcohol with a dibasic acid, while the remaining valence or valences are bound to an alkyl, aryl, hydroaromatic or ,heterocyclic radial.

The compounds are represented by the type formula wherein R stands for a radical selected from the group consisting of alkyl, aryl, hydroaromatic or heterocyclic radicals, X for the radical of an ester of a mercapto alcohol having from 2 to 4 carbon atoms with an aliphatic aromatic or hydroaromatic dibasic acid containing from 6 to 12 carbon atoms, and n for an integral number from 1 to 3.

Examples for R are alkyls, such as methyl, ethyl, butyl, octyl, dodecyl, and octadecyl; aryls, such as phenyl, tolyl, or xylyl; oxyalkyl and oxyaryl, such as C3H7O, C H O,

The novel tin compounds used according to our invention are either oily liquids of high viscosity or amorphous solids whose composition has in each case been ice ascertained by analysis. Most of them are soluble in many organic solvents, for instance in ether, benzene, toluene, chloroform, carbontetrachloride, etc.

A general method to prepare these compounds is first to prepare the desired ester of the mercapto alcohol and dibasic acid chosen, and subsequently to react the ester with an organic tin halide, organic tin oxide, or a stannonic acid, containing an organic radical.

Then invention will now be illustrated by a number of examples, but it should be understood that these are given by way of illustration and not of limitation and that many variations in the compounds given and the amounts indicated can be made without departing from the spirit of the invention and the scope of the appended claims.

PEPARATION OF TIN DERIVATIVES Example 1 The preparation of dibutyl-tin di-mercapto ethanol d pat S (CH2)2,O.CO

S(CH2)2O.CO

(Ca da-Sn Two mols of mercapto ethanol, one mol of adipic acid, cc. benzene, to which 0.3 gram p-toluene sulfonic acid were added, are refluxed and 36 cc. water eliminated by azeotropic distillation.

Subsequently, one mol of dibutyl tin oxide is added, refluxing being continued until another 18 cc. of water have distilled off. Slight impurities are filtered 0E and the benzene is distilled oflf. The residue is a very viscous liquid of a brownish color. It is soluble in ether, chloroform, carbontetrachloride, benzene, toluene, xylene, and other organic solvents.

ANALYSIS Sn S Cale. values Found values.

Example 2 Preparation of tribenzyl tin dimercapto butanol azelaic acid ester (CtH CHn) rSn- S.(C HDAOwC O (CHM (CQHQCHQ)3 SI1 S (GHZ)OO P$0 ANALYSIS Sn S Cale. values 20. 65 5 6 Found values 21. 2 5 4 Example 3 Preparation of mono-isopropyl tin di-mercapto ethanol terephthalate Two mols of mercapto ethanol, one mol of terephthalic acid, 150 cc. benzene, to which 0.5 paratoluene sulfonic acid were added, are refluxed until 36 cc. Water are eliminated by azeotropic distillation.

Subsequently 2/ 3 mol of isopropyl stannonic acid, prepared as described in the literature, are refluxed with the ester until the theoretic amount of water is driven off. Slight impurities are filtered off and benzene is removed by distilling. The residue in this case is a brown solid which represents obviously a material polymerized to some extent and which is only slightly soluble in benzene and is much better soluble in chloroform.

ANALYSIS Sn S Cale. values 20. 1 16. 35 Found values 19. 8 16.6

100 parts of vinylite VYNW (vinyl chloride and acetate copolymer), 50 parts dioctyl phthalate, and 2 parts of the product of Example 1 as stabilizer are mixed by tumbling for a period of one hour. The whole mass is then transferred to a Banbury mixer and fused for min. at a temperature of approximately 300 F. It is then dropped and transferred to a warm-up mill, whose roll temperature is likewise maintained at 300 F. The material is then fed as needed to a 3 or 4 roll calender. The roll temperatures of the calender range from 280-350 F. The vinyl compound is calendered into a film at 0.004 inch or any other desirable gage.

4 Example 5 The following procedure is used to advantage in making a finished solution of the resin. We use parts of vinylite VYNW (Vinyl chloride and acetate copolymer) along with 40 parts of tricresylphosphate. This is weighed into a dry blender; 1 part of stabilizer (made as described in Example 2) is then added. The whole mass is agitated by tumbling for 30 minutes and then transferred to a 2-roll mill whose roll temperatures are about 240 F. The mass is fluidized on the mill and then sheeted into strips which are added to a mixture consisting of 3 parts of methyl ethyl ketone and 1 part of toluene in .a conventional mixer. The compound is agitated at room temperature in the mixer until complete solution results. The proportion of solvent used will vary with the concentration of solution desired, as, for instance, from 500 to 3,000 parts of solvent to 100 parts of the vinyl chloride resin used.

In the above Example 4 and 5, equally satisfactory results will be obtained, if we use the stabilizer made in accordance with Example 3.

Example 6 Comparison tests were made in which chlorinated paraffin was heated over a period of time, without any addition on the one hand, and with addition of a stabilizer made according to the invention, on the other hand.

In these tests, a nitrogen current was passed through chlorinated paraffin containing 40% chlorine, at a temperature of F. for 12 hours. During the test, the parafiin lost 10% chlorine.

The same chlorinated paraffin, to which 3% of the products obtained in one of the Examples 1, 2 or 3, were added, was treated in a similar manner and showed a loss of only 1% chlorine, after 12 hours.

What we claim is:

1. A stabilized polyvinyl chloride resin containing 0.1% to 10% by weight of a compound selected from the group consisting of compounds corresponding to the formulae (R Sn) X, R SnX and (R.Sn) X wherein R stands for an alkyl radical, and X for the radical of a diester of a mercapto alcohol having from 2 to 4 carbon atoms with a saturated aliphatic dicarboxylic acid, and wherein all the sulfur atoms of the mercapto alcohols are linked to the tin.

2. A stabilized polyvinyl chloride resin selected from the group consisting of polyvinyl chloride and copolymers of vinyl chloride with a preponderant amount of vinyl chloride containing from 0.1 to 10% by weight of dibutyl tin dimercaptoethanol adipate, wherein the sulfur of the mercapto ethanol radical is linked to the tin.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A STABILIZED POLYVINYL CHLORIDE RESIN CONTAINING 0.1% TO 10% BY WEIGHT OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF COMPOUNDS CORRESPONDING TO THE FORMULAE (R3SN)2X, R2SNX AND (R.SN)2X3 WHEREIN R STANDS FOR AN ALKYL RADICAL, AND X FOR THE RADICAL OF A DIESTER OF A MERCAPTO ALCOHOL HAVING FROM 2 TO 4 CARBON ATOMS WITH A SATURATED ALIPHATIC DICARBOXYLIC ACID, AND WHEREIN ALL THE SULFUR ATOMS OF THE MERCAPTO ALCOHOLS ARE LINKED TO THE TIN. 